Further clean up GpuDataManager{Impl}{Private}.

Now we no longer do a bunch of heavy ops (like collect GPUInfo, etc) in
Initialize(), we can simply merge it into constructor and that enables
some simplification.

BUG=808119
TEST=bots
[email protected],[email protected]

Change-Id: I696a146221ef32319a14294a0193c1659703295d
Reviewed-on: https://chromium-review.googlesource.com/910044
Commit-Queue: Zhenyao Mo <[email protected]>
Reviewed-by: Antoine Labour <[email protected]>
Cr-Commit-Position: refs/heads/master@{#535816}
5 files changed